Unlike Android that allows you to customize and create a ringtone easily, iPhone only uses M4R files as ringtones, and the length is limited to 40 seconds. Therefore, it means you have to extract the audio less than 40 seconds from an MP4 video and then convert it to iPhone ringtone format - M4R. Sounds complicated? No worries, with the help of HD Video Converter Factory Pro – a handy and all-around A/V conversion utility, all you need to do is just click your mouse a few times. Now, let's see how easy it is to convert MP4 to ringtone with this powerful tool.